SPC AC 192000

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0300 PM CDT Sun May 19 2024

   Valid 192000Z - 201200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   OK...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE PLAINS
   AND SOUTHEAST FLORIDA...

   ...SUMMARY...
   Numerous severe thunderstorms capable of widespread damaging winds
   and giant hail are expected this afternoon and evening across
   portions of Kansas and northern Oklahoma.  Gusts of 75-100 mph are
   possible, along with very large hail and a few tornadoes.

   ...20z Update...
   No consequential changes to forecast reasoning and current Day 1
   Outlook. Main severe risk as depicted by MDT/ENH risks appears to be
   steadily unfolding generally as expected, including intense storm
   development along the boundary in north-central Kansas, with
   higher-based storms also steadily increasing across southeast
   Colorado and the Oklahoma/Texas Panhandles. Semi-discrete supercells
   are still expected before cell mergers/aggregating cold pools lead
   to potentially significant severe wind potential across
   southwest/central Kansas and nearby northern Oklahoma, which is
   consistent with latest WoFS forecasts.

   ..Guyer.. 05/19/2024

   .PREV DISCUSSION... /ISSUED 1120 AM CDT Sun May 19 2024/

   ...KS/OK...
   Morning water vapor imagery shows a shortwave trough over northern
   AZ.  This feature is expected to accelerate eastward this afternoon,
   with an associated mid/upper level jet max nosing into the central
   High Plains.  This will lead to scattered high-based thunderstorms
   over southeast CO by mid-afternoon, capable of locally gusty winds
   and hail.  As this activity builds eastward across the dryline,
   rapid intensification of supercell storms is expected.  Forecast
   soundings show a relatively deep boundary-layer, but large CAPE
   values and dry-adiabatic mid-level lapse rates.  Deep-layer shear
   profiles will promote rotating storms capable of very large hail,
   damaging winds, and a tornado or two across southwest KS and any
   more isolated cells that form southward along the dryline into
   western Oklahoma.

   As this activity moves eastward, congealing outflows will likely
   result in a fast-moving QLCS capable of widespread significant wind
   damage for a few hours.  It remains unclear how far east this threat
   will persist, but given current model guidance, will not change the
   ongoing bounds of the ENH/MDT risk areas in eastern KS.

   ...Eastern FL...
   A surface cold front is sagging southward across the central FL
   peninsula today.  Along and ahead of the front, very warm/moist
   low-level conditions persist with dewpoints in the low-mid 70s and
   strong daytime heating occurring.  It appears likely that at least
   scattered thunderstorms will form near/along the east-coast sea
   breeze later this afternoon.  Any storm that can intensify before it
   moves offshore would potentially acquire supercell characteristics
   and pose a risk of large hail and damaging wind gusts.  See
   mesoscale discussion #829 for further details.

   ...SD/NE/Northeast CO...
   Strong heating is occurring across much of western SD/NE, where
   southerly low-level winds are helping to transport 50s dewpoints in
   the region.  A weak shortwave trough currently over WY will approach
   the region by mid-afternoon, helping to initiate scattered
   thunderstorms from the Black Hills region southward into western NE
   and northeast CO.  These storms will be relatively high-based, but
   in an environment of sufficient vertical shear to promote organized
   multicell or supercell structures capable of damaging winds and
   hail.  Storms will persist through much of the evening and spread
   into central SD/NE before weakening.

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